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russ_watters
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Bernoulli's compressible flow equation will get you close.xxChrisxx said:There is a formula to work out the critial pressure drop for choked flow, but I can't remember it at present.
Bernoulli's compressible flow equation will get you close.xxChrisxx said:There is a formula to work out the critial pressure drop for choked flow, but I can't remember it at present.
PaulS1950 said:He got the power with boost and got the mileage by not using the horse power.
The amount of power used is proportional to the amount of fuel burned.
Build a light and aerodynamic car with a relatively small engine with a turbo-charger on it and then cruise at 60 mph using a light throttle, no boostand an electronic engine management system and you can easily duplicate or even exceed those results.
The biggest factor in mileage is the nut behind the wheel (steering wheel that is). Just by changing your driving habits you can get an increase of up to 50% in your mileage. Add to that skinny, hard tires running on low friction bearings (loose but not sloppy) and a completely locked up drive train (rotating as a single member) and you begin to understand that we as drivers waste a lot more fuel than our cars do.
Just lift your foot halfway off the gas when you get to the speed you want to cruise at.jakksincorpse said:how exactly do you not use the horsepower? like give your motor lots of low end torque to cruise on?
jakksincorpse said:i don't think there would be a huge loss. you can freely spin a turbocharger with ur hand. i figured running the hot side of a charger through the auxilery belt to drag out the exhaust would be pretty nifty. maybe if there were some changes in design of the motor this could be useful at high rpms.
Lsos said:When you "freely spin a turbocharger with ur hand" you are hardly doing anything. A turbocharger does work when it's plumbed into an engine that provides a resistance. That, and when it's spinning at something like 100,000rpm...which is much more than you can hope to accomplish with your hand.
Again, you are underestimating how much brute force it can take to move air around.
jakksincorpse said:so in the end, god i swear I've re-written this 4 times. so i'll keep it simple
more low end torque will increase mpg with smarter driving because...the engine is working more efficiently and using less fuel?
jakksincorpse said:i wasnt underestimating, i was making an observation, there are "fake" superchargers called prochargers that use the same design i stated only shove air into the motor,
i've been told the suction idea won't work so the idea is irrelevent.
Redbelly98 said:A 20" diameter wheel has a circumference of 63" or 5.2 feet. So it's about 1000 revolutions per mile:
1000 x 5.2' = 5200' = 1 mileAt 642 rpm, it takes about 1.5 minutes to get to 1000 revs or 1 mile.
jakksincorpse said:
Yes.jakksincorpse said:did u get the circumfrence by multiplying 20" by pi?
jakksincorpse said:how much torque is required to keep a car at 60mph?
like 3000lb weight, 0.30 coefficient of drag, 63" wheel circumfrence